Case IH 19578 – DCU (Dosing Control Unit): CAN receive frame E2SCR (Dosing status not in range) / P0600 Serial Communication Link

The control module is failing to receive the expected E2SCR data frame over the SAE J1939 datalink. Specifically, the system is flagging that the 'Dosing status' signal is not in the expected range, meaning the module cannot verify the current state of the exhaust aftertreatment (DEF/AdBlue) dosing system.

• Tier 4a
• Case IH Magnum Series (235-340 Series 4, 315, 340)
• Case IH Steiger Series (350-600)
• Case IH Puma Series
• Case IH Axial-Flow Combines (7230, 8230, 9230)

1. 1

   Inspect the SAE J1939 CAN bus wiring harness between the DCU and the main Engine Control Module (ECM) for chafed wires, broken connections, or bent/corroded pins at the DCU connector.

2. 2

   Measure the resistance of the CAN bus network to ensure the terminating resistors are intact (typically 60 ohms across the CAN High and CAN Low pins with the battery disconnected).

3. 3

   Verify that the DCU is receiving proper voltage and has a clean ground connection, as a drop in power can cause the module to drop off the CAN network.

4. 4

   Connect a diagnostic tool (such as CNH EST) to check for software updates or other active communication codes (like 19579 for timeout errors) that might point to a broader network failure.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical shorts during harness inspection.

2. 2

   Locate DCU

   Locate the Dosing Control Unit (DCU) near the DEF/AdBlue tank and pump assembly.

3. 3

   Clean contacts

   Disconnect the main harness from the DCU. Clean the contacts with electrical contact cleaner and apply dielectric grease.

4. 4

   Repair wiring

   Repair any damaged CAN wiring (CAN High / CAN Low) found during the diagnostic phase.

5. 5

   Clear fault codes

   Reconnect the battery and turn the key to the ON position. Use the OEM diagnostic tool to clear the fault codes.

6. 6

   Evaluate DCU

   If the code immediately returns and the wiring/power/ground checks are perfect, the DCU has likely suffered an internal failure and must be replaced.

7. 7

   Replace DCU

   Remove the defective DCU and install the replacement module.

8. 8

   Flash DCU

   Flash the new DCU. Replacement modules are shipped blank and require software installation using the CNH Electronic Service Tool (EST). CNH requires troubleshooting verification before issuing the programming passwords.